Interpretive Summary: In order to determine if there are differences in pork tenderness between breeds or lines of swine, researchers must be able to accurately and efficiently measure tenderness on a large number of samples. Thus, experiments were conducted to determine if advances that had been made in the objective assessment of beef tenderness could be adapted for evaluation of pork. It was determined that pork loin muscle tenderness could be accurately evaluated using rapid cookery with a belt grill and rapid measurement of meat tenderness using a procedure called slice shear force. Use of belt grill cookery and the slice shear force technique could reduce time requirements which would reduce research costs.

Technical Abstract:
The present experiments were conducted to determine if improved beef longissimus shear force methodology could be used to assess pork longissimus tenderness. Specifically, three experiments were conducted to 1) determine the effect of belt grill (BG) cookery on repeatability of pork longissimus Warner-Bratzler shear force (WBSF), 2) compare the correlation of WBSF and slice shear force (SSF) with trained sensory panel tenderness ratings, and 3) estimate the repeatability of pork longissimus SSF for chops cooked using a BG. In experiments 1 and 2, the longissimus was removed from the left side of each carcass (Exp. 1, n = 25; Exp. 2, n = 23) at 1 d postmortem and immediately frozen to maximize variation in tenderness. In Exp. 1, chops were cooked with either open-hearth electric broilers (OH) or BG and WBSF was measured. Percentage of cooking loss was lower (P < .001) and less variable for chops cooked with a BG (23.2%; SD = 1.7%) vs OH (27.6%, SD = 3.0%). Estimates of the repeatability of WBSF were similar for chops cooked with OH (.61) and BG (.59). Although significant (P < .05), differences in WBSF (4.1 vs 3.9) between cooking methods accounted for less than 5% of the total variation in WBSF. In Exp. 2, the correlation of SSF (r = -0.72) with trained sensory panel tenderness ratings was slightly stronger than the correlation of WBSF (r = -0.66) with trained sensory panel tenderness ratings indicating that the two methods were equally effective at predicting tenderness ratings. In Exp. 3, duplicate samples were obtained from 372 carcasses at 2 and 10 d postmortem, cooked with BG, and SSF was determined. The repeatability of SSF was 0.90 which is comparable to our repeatability estimates for beef and lamb (0.91 and 0.95, respectively). Use of BG cookery and SSF could facilitate the collection of accurate pork longissimus tenderness data. Time and labor savings associated with BG cookery and the SSF technique should help to reduce research costs.